Angela Rayner MP is demanding that United Utilities pay the Living Wage to its water workers.
The company made £271.2 million profit in 2014/15 and its salaries for senior staff reached up to £2.375 million in the same year.
Yet many of its staff still receive less than £8.25 an hour in the North West and £9.40 an hour in London.
The UNISON campaign “Making Waves for the Living Wage” has resulted in six major water companies signing up as Living Wage employers – but so far United Utilities have failed to join.
Angela said: “I am concerned that United Utilities have yet to make this commitment.
“I believe that it is wrong for water companies to pay wages below the Living Wage to people providing services on their behalf.
“18 privately owned water companies in England and Wales had retained excess profits of £1.2bn over the past five years.
“Given this, I see no reason why United Utilities or indeed the water sector as a whole cannot afford to pay the Living Wage.
“I know from my meetings with constituents that being paid less than the Living Wage is a big problem for many workers in Ashton-under-Lyne.
“Failure to pay the Living Wage results in people being unable to provide for themselves and their families.
“I know that when I pay my water bill each month – and it isn’t getting any cheaper – I expect to see it spent on decent wages for vital staff in the water industry.
“I believe that every employer in the water sector including customer call centre operators, catering staff, cleaners and security guards need to be paid the wages they need to live on.
“This is a vital campaign and I am proud to support every effort to make the water industry the leading sector paying the National Living Wage.”